“…[79][80] According to the chemical structures of aglycones, polyphenols may be classified in flavonoids, stilbenes, lignans, flavonoids, hydrobenzoic and hydroxycinnamic acids. 81 The presence of several phenolic and hydroxycinnamic acids (sinapic acid, gallic acid, p-coumaric acid, caffeic acid, vanillic acid, protocatechuic acid, ferulic acid,), and flavonoids (catechin, quercetin, myricetin, kaempferol) have been reported in HNs. In particular, the main polyphenolic subclass comprises of monoand oligomeric flavan 3-ols, which accounts between 34.2 and 58.3% in HN kernels, with a total phenolic content ranging from 491.2 to 1700.4 mg of gallic acids equivalent/kg.…”